Curvularia leaf spot

Curvularia leaf spot is a destructive plant disease caused by the fungal pathogen Curvularia intermedia. This fungus belongs to a group of ubiquitous plant pathogens capable of infecting a wide range of host plants, leading to severe yield losses in both agricultural and horticultural sectors worldwide.

The disease primarily targets graminaceous crops, including maize, sorghum, wheat, rice, and various turfgrass species. It can attack plants at any developmental stage, though symptoms are most frequently observed during periods of active growth and high humidity, affecting leaves, stalks, and reproductive parts like ears or panicles.

Symptoms typically present as small, dark brown or necrotic lesions on the leaves, often surrounded by a characteristic yellow chlorotic halo. As the infection progresses, these spots expand, coalesce, and result in extensive tissue death, causing premature blighting of the canopy and significantly reducing the plant's photosynthetic capacity.

The development of Curvularia intermedia is highly dependent on environmental conditions, specifically high temperature and sustained humidity. The fungus produces abundant conidia, which act as the primary inoculum, spreading through wind, irrigation water, and rainfall splash. It persists in infested crop debris, soil, and seeds, facilitating carry-over from one growing season to the next.

Management strategies for this disease rely on an integrated approach, starting with the use of pathogen-free seeds and disease-resistant hybrids. Cultural practices, such as crop rotation, effective removal of crop residues, and proper field drainage, are essential for limiting primary inoculum sources. Chemical control using registered foliar fungicides is recommended when environmental conditions are optimal for disease spread.